三峡库区水位变幅对奉节何家坡滑坡稳定性影响分析

为了更好地研究在三峡库区增大库水降幅条件下奉节何家坡滑坡稳定性,预测评判其发展趋势,通过现场地质调查和勘探,分析了何家坡滑坡的变形模式与形成机制,并考虑了库水位骤降作用。利用Geo Studio有限元分析软件对滑坡在增大库水位变幅的极端工况下进行渗流场模拟与稳定性计算。研究表明,何家坡滑坡变形主要集中在坡体前缘与中部,表现为逐级牵引式变形破坏,库水位降幅1.2 m/d条件下整体处于基本稳定状态。随着库水位下降速率增大,滑坡稳定性系数不断降低,属典型的动水压力型滑坡。

Analysis on impact from water level fluctuations of Three Gorges Reservoir on stability of Hejiapo Landside in Fengjie

In order to better study the stability of Hejiapo Landslide in Fengjie under the increase of the drawdown amplitude of the reservoir water level，and predict and appraise the developing trend of it，the deformation mode and formation mechanism of Hejiapo Landslide are analyzed and the effect of the rapid drawdown of water level is considered through the in situ geological investigation and exploration. Furthermore，the simulation of seepage field and stability calculation for the landslide under the extreme operation condition of increase of the water level fluctuation are made with the finite element analysis software—GeoStudio. The study result shows that the deformation of Hejiapo Landslide is mainly concentrated at the front edge and the mid-part of the slope，which presents a step by step pull-deformation failure and is wholly under a basically stable status under the condition with the drawdown amplitude of the reservoir water level of 1.2 m/d. The stability coefficient of the landslide is lowered along with the increase of the rate of the drawdown of the reservoir water level，thus it belongs a typical landslide caused by hydrodynamic pressure.